1. Field
The described technology relates generally to a metal sheet holding device, and more particularly, a metal sheet holding device for manufacturing a pattern mask for manufacturing flat panel displays.
2. Description of the Related Art
Organic light emitting diode displays have been known to be used in flat panel displays. The organic light emitting diode display is provided with a pixel circuit and an organic light emitting diode (OLED) for each pixel, and displays an image by combining light emitted from a plurality of organic light emitting diodes. The organic light emitting diode includes a pixel electrode, an organic emission layer, and a common electrode.
An organic emission layer may be formed by a deposition method using the pattern mask. The pattern mask forms a plurality of opening parts corresponding to the organic emission layer and is fixed to a frame in a condition where tension is applied to the pattern mask. The pattern mask fixed to the frame is arranged on a substrate in a deposition chamber including a deposition source. Organic material that is evaporated from the deposition source is deposited on portions of the substrate that are exposed through the opening parts of the pattern mask, thus forming the organic emission layer.
The pattern mask can be a fine metal mask (FMM) formed of a metal sheet and is manufactured using, for example, invar (iron-nickel alloy), a stainless steel (SUS), or the like. In accordance with the development of laser micro-machining processes, research into a technology of forming the opening parts in the metal sheet using a picosecond (ps) laser (e.g., ultrashort pulse laser) has been conducted.
The above information disclosed in this Background section is provided for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form prior art.